However that indicator isn't present when server messages are retrieved using the property('Message',n) or property('MessageText',n) functions. The exact text used to indicate the error is hard to predict and it is particularly difficult to get the additional information (eg the second line in the messages above). Is there, or could there be, a way of retrieving the indicator as well?

I could grep the output file - but that does seem a bit of a round about way of doing it!